The invention relates to a tempering device for printing presses with compression refrigerating plant with a condenser and an evaporator, in which a coolant circulates, a free cooling circuit, in which a coolant, especially water, circulates, a process water cycle, in which a coolant for printing rollers or a fountain solution for offset printing circulates, and heat-exchanger means for cooling the cycling process water with the help of the compression refrigerating plant and/or of the free cooling cycle.
Various embodiments of tempering systems for printing presses are known. As a rule, they are cooling systems, since a certain amount of heating, which can affect the printing quality, necessarily occurs during the operation of the printing press. The cooling can take place by water cooling of the friction rollers with the help of a pipeline system passing through these rollers or, in the case of offset printing, by means of a cooled fountain solution, which is applied on the rollers. Occasionally, cool air is also blown on certain parts or components of the printing presses.
Refrigeration plants, which have relatively high energy consumption, are required for these systems. Systems, which are cooled directly or indirectly by refrigeration plants, that is, compression refrigerating plants, are known. In most cases, directly cooled systems function by cooling the process medium, in most cases water or a mixture of water and glycol, directly by an evaporating coolant in the evaporator of a compression refrigerating plant, constructed as a heat exchanger. Directly cooled systems either have an integrated air-cooled or water-cooled condenser or an external air-cooled condenser.
Indirectly cooled systems generally are cooled by water. In these systems, the process water is cooled in an integrated water/water heat exchanger by the cooling water of an external source. In some cases, the process water is also cooled by mixing it with the cooling water of the external source. Since a separation of the cycles necessarily is impossible, this method is not suitable for cooling fountain solution.
Directly cooled systems, with a water-cooled condenser in the cooling cycle, obtain their cooling water usually from central cooling water systems. These frequently are systems with free coolers or evaporative coolers. The temperature level of the cooling water of these external cooling systems is always low enough, in order to ensure adequate cooling of the water-cooled condenser of the cooling plant. Likewise, the temperature level in most cases is sufficient for supplying other peripheral equipment at printing presses, such as air-supplying cabinets or drying cabinets, adequately with cooling. However, since the temperature level of this cooling water is not always low enough, so that this cooling water can be used by means of a water/water heat exchanger for cooling the process water directly for cooling the friction rollers in the printing press, such systems are not being used at the present time.
The conventional systems have the disadvantage, in particular, that they use much energy and, correspondingly, have high operating costs.